Testing for Early Detection of Alzheimer’s Disease

Diagnosing the BrainThe familiar symptoms of Alzheimer’s disease include forgetfulness, speech difficulties, confusion and inability to form memories. But the telltale biological markers of Alzheimer’s disease begin to take hold in the brain well before any of these outward signs become apparent.

In Alzheimer’s patients, amyloid plaques and tangles of tau proteins form and accumulate in the brain which can lead to functional impairment. While these formations can be detected through positron emission tomography (PET) scan or cerebrospinal fluid analysis, such analyses are very expensive and invasive and not widely available.

Duke Han, PhD, a neuropsychologist at Keck School of Medicine of the University of Southern California, wondered if there might be a simpler way to test for early Alzheimer’s disease without having to resort to expensive or invasive testing.

In his study, Dr. Han and his team wanted to see if performance on cognitive tests could predict whether people had the amyloid plaques and tau proteins associated with Alzheimer’s. Dr. Han’s team found that subjects who had amyloid plaques did indeed perform worse on tests of cognitive function, memory, language and attention than subjects without these plaques. The presence of amyloid plaques and tau proteins in the subjects was confirmed by PET scan or cerebrospinal fluid tests.

These results suggest that cognitive testing should be incorporated into routine evaluations of older people to help identify and diagnose early Alzheimer’s as soon as possible in order to improve management, prevention and care strategies at the earliest possible stage before the more severe symptoms manifest. A baseline could be established from an initial evaluation, then be used to track whether or not a patient is experiencing cognitive decline over time.

More about this study can be found in Neuropsychology Review and in this Keck School of Medicine press release.